Term
What is moment of inertia? |
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Definition
•the inertial property for rotating bodies
• represents resistance to angular acceleration
• based on both mass and the distance the mass is distributed from the axis of rotation
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Term
____is the sum of the products of each particle’s mass (m) and the radius of rotation (r) for that particle squared. I = Smr2 |
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Definition
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Term
| what is the radius of gyration? |
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Definition
•distance from the axis of rotation to a point where the body’s mass could be concentrated without altering its rotational characteristics
• used as the index for mass distribution for calculating moment of inertia:
I = mk2 |
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Term
| Knee angle affects the moment of inertia of the swinging leg with respect to the hip because of changes in the |
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Definition
| radius of gyration for the lower leg and foot. |
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Term
| what is angular momentum? |
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Definition
•quantity of angular motion possessed by a body
• measured as the product of moment of inertia and angular velocity:
H = Iw
H = mk2w |
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Term
What is the principle of conservation of angular momentum? |
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Definition
The total angular momentum of a given system remains constant in the absence of external torques.
H1 = H2
(mk2w)1 = (mk2w)2 |
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Term
| When angular momentum is conserved, there is a tradeoff between |
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Definition
| moment of inerta and angular velocity |
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Term
What produces change in angular momentum? |
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Definition
angular impulse - the product of torque and the time interval over which the torque acts:
T t = DH
T t = (Iw)2 - (Iw)1 |
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Term
What are the angular equivalents of linear kinematic quantities? |
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Definition
Linear Angular
mass (m) moment of inertia (I = mk2)
force (F) torque (T = Fd )
momentum (M=mv) angular momentum (H=mk2w)
impulse (Ft) angular impulse (Fd t) |
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Term
What is the angular law of inertia? |
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Definition
| A rotating body will maintain a state of rest or constant rotational motion unless acted on by an external torque that changes the state |
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Term
What is the angular law of acceleration? |
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Definition
A net torque causes angular acceleration of a body that is:
• of a magnitude proportional to the torque
• in the direction of the torque
• and inversely proportional to the body’s moment of inertia |
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Term
| What is the angular law of acceleration |
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Definition
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Term
What is the angular law of reaction? |
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Definition
• For every angular action, there is an equal and opposite angular reaction.
• When one body exerts a torque on a second, the second body exerts a reaction torque that is equal in magnitude and opposite in direction on the first body. |
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Term
What is centripetal force?
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Definition
(force directed toward the center of rotation for a body in rotational motion)
mv2
Fc = r
Fc = mrw2 |
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